The art and science of instrumented flight training involves the measurement of the position and dynamic behavior of the aircraft so that it may be monitored for safety purposes, and replayed to the student for debriefing and assessment purposes. Merely by way of example, a simulation system, such as those described the '628 Application and the '730 Application, can be used to replay (and/or provide a simulation of) a flight training mission, and positional and dynamic data gathered during the training mission can be used as input to the replay and/or simulation engine.
In most phases of flight, traditional accuracies of 3 to 30 meters are sufficient to provide good quality training value. However, during ground operations (engine start, taxi, take-off and landing) or near-ground operations (approach, round-out, flair or autorotation), precise measurements (less than one meter uncertainty) generally are required to avoid the appearance during replay that the aircraft is descending below the terrain, or flying too high above it. In addition, such precision can be useful in other contexts, such as when providing in-flight data to a pilot via cockpit instruments.
Traditional methods of achieving the requisite accuracies involve high accuracy sensor suites or real time data links, all of which drive the cost and complexity of the instrumentation beyond the reach of the average primary flight training provider. For this reason, instrumented flight training has historically been reserved for students flying high performance aircraft during advanced phases of flight training. Because of recent advances (such as those described by the '628 Application and the '730 Application, for example), relatively low cost aircraft can now be used for instrumented flight training of even beginning pilots. These advances, among others, create a need for a relatively low-cost method of providing accurate and precise altitude data.